How can magnetic attraction pass through paper?
A magnet has an invisible magnetic field around it. A small compass turns at different positions. The curved lines in the picture help map direction; they are not threads flowing out of the magnet.
Steel contains many tiny magnetic regions. A nearby magnet changes their arrangement, temporarily making the paper clip act like a small magnet too. It is attracted toward the magnet.
Ordinary thin paper hardly blocks this field, so the clip can be attracted through it. Move the magnet farther away and the attraction weakens. Try a wooden bead or plastic button and compare.
Three changes, one at a time
- Add paper. One sheet, then five, between clip and magnet. Does the pull change much? What about a plastic sheet?
- Pull away. Keep everything else fixed and slowly increase the distance. Does the pull fade gently or vanish suddenly?
- Swap materials. Try a wooden bead, a plastic button and the steel clip. Which ones barely move?
Guess, then test: if you flip the magnet’s N and S poles, is the steel clip still attracted?
Dipole fields, magnetization and limits
More: a closer explanation
A magnetic field fills the space around a magnet. It is invisible but real: place a small compass anywhere nearby and the needle turns along the local field. The curved “field lines” are only a map of those directions—nothing flows along them, and the force is not confined to the lines.
Inside a steel paper clip live countless magnetic domains—tiny magnetic regions. Left alone they point every which way and cancel out. When the magnet comes near, the regions closest to it align first, and the clip briefly becomes a small magnet itself.
The magnetized end facing the magnet carries the opposite polarity, and the field grows stronger toward the magnet. That pull toward the stronger field is the attraction—and paper does not stop it, because ordinary thin paper barely impedes a magnetic field (it only adds a whisker of distance).
Open: how fast does the field fall with distance?
Far from the magnet’s ends, the field strength decays with the cube of the distance:
In this far-field approximation, doubling the distance reduces field strength to about one eighth. That is not the force ratio: the pull also depends on the field gradient and how the clip becomes magnetized. The model uses a smoothed dipole so the near field stays finite.
Open: magnetization and hysteresis
Steel is ferromagnetic: its domains align readily with an external field. After the magnet leaves, hard steel keeps a little magnetism (remanence) while soft iron lets go almost at once. The model does not simulate hysteresis; it only shows the “align when close, relax when far” trend. Copper and aluminium are not ferromagnetic—an ordinary magnet barely tugs them.
Limits of the model
Field lines are a direction map, and the clip’s pull is shown only as a relative strength—no invented newton or tesla readings. Ordinary paper is approximated as transparent to the field; a thick steel plate would change the answer completely.